Identification of avian polyomavirus and its pathogenicity to SPF chickens

The research aimed to study an Avian polyomavirus strain that was isolated in Shandong, China. To study the pathogenicity of APV in SPF chickens, and provide references for epidemiological research and disease prevention and control of APV. The genetic characterization of APV strain (termed APV-20) was analyzed and the pathogenicity of APV was investigated from two aspects: different age SPF chickens, and different infection doses. The results revealed that the APV-20 exhibits a nucleotide homology of 99% with the other three APV strains, and the evolution of APV In China was slow. In addition, the APV-20 infection in chickens caused depression, drowsiness, clustering, and fluffy feathers, but no deaths occurred in the infected chickens. The main manifestations of necropsy, and Hematoxylin and Eosin staining (HE) showed that one-day-old SPF chickens were the most susceptible, and there was a positive correlation between viral load and infection dose in the same tissue. This study showed that SPF chickens were susceptible to APV, and an experimental animal model was established. This study can provide a reference for the pathogenic mechanism of immune prevention and control of APV

Natural Hirudin Increases Rat Flap Viability by Anti-Inflammation via PARs/p38/NF-κB Pathway

The present study aimed to evaluate the effect of natural hirudin on rat random skin flap viability and to determine the mechanism. Forty-eight rats were randomly divided into 2 groups. After the dorsal skin flap operation (3 cm × 10 cm in size), subcutaneous injections of 6 ATU hirudin were administered to group H (n=24) every 12 h, while group C (n=24) received an equal volume of 0.9% normal saline. Six rats from each group were euthanized 1, 2, 4, and 7 days after the operation. A full skin sample was collected from these rats to measure the p38-mitogen-activated protein kinase (p38-MAPK), phospho-p38- (Pp38-) MAPK, nuclear factor-κB (NF-κB) p65, phosphor-NF-κB (pNF-κB) p65, tumour necrosis factor- (TNF-) α, interleukin- (IL-) 6, and intercellular adhesion molecule- (ICAM-) 1 levels via western blot (WB) assays. The results showed that flap viability was significantly higher in the hirudin-treated group, which showed a reduced inflammatory response compared with the control group. The Pp38/p38, pNF-κB p65/NF-κB p65, TNF-α, IL-6, and ICAM-1 levels in the hirudin-treated group were lower than those in the control group. The results demonstrated that hirudin could improve random skin flap viability and suggested that this effect maybe occurs by blocking the thrombin/proteinase-activated receptors (PARs)/p38/NF-κB signalling pathway, thus decreasing the inflammatory response

Disturbance of the let-7/LIN28 double-negative feedback loop is associated with radio- and chemo-resistance in non-small cell lung cancer

<div><p>Radio- and chemo-resistance represent major obstacles in the therapy of non-small-cell lung cancer (NSCLC) and the underlying molecular mechanisms are not known. In the present study, during induction of radio- or chemo-resistance in NSCLC cells, dynamic analyses revealed that decreased expression of let-7 induced by irradiation or cisplatin resulted in increased expression of its target gene <i>LIN28</i>, and increased expression of LIN28 then contributed to further decreased expression of let-7 by inhibiting its maturation and biogenesis. Moreover, we showed that down-regulation of let-7 and up-regulation of LIN28 expression promoted resistance to irradiation or cisplatin by regulating the single-cell proliferative capability of NSCLC cells. Consequently, in NSCLC cells, let-7 and LIN28 can form a double-negative feedback loop through mutual inhibition, and disturbance of the let-7/LIN28 double-negative feedback loop induced by irradiation or chemotherapeutic drugs can result in radio- and chemo-resistance. In addition, low expression of let-7 and high expression of LIN28 in NSCLC patients was associated significantly with resistance to radiotherapy or chemotherapy. Therefore, our study demonstrated that disturbance of the let-7/LIN28 double-negative feedback loop is involved in the regulation of radio- and chemo-resistance, and that let-7 and LIN28 could be employed as predictive biomarkers of response to radiotherapy or chemotherapy in NSCLC patients.</p></div

Let-7 family miRNAs regulated radio- and chemo-resistance by targeting <i>LIN28</i>.

<p><b>(A)</b> Luciferase assays of let-7 targeting effects on <i>LIN28</i>. Mutations were generated in the <i>LIN28A</i> 3′-UTR and <i>LIN28B</i> 3′-UTR sequence in the complementary site for the seed region of let-7 as indicated. <b>(B)</b> mRNA and protein levels of LIN28 were decreased in A549/IR and A549/DDP cells after transfection of let-7 mimics and increased in A549 cells after transfection of let-7 inhibitors, as detected by RT-PCR and western blotting. <b>(C)</b> Overexpression of let-7 decreased resistance to irradiation in A549/IR cells or to cisplatin in A549/DDP cells significantly. <b>(D)</b> Inhibition of let-7 increased resistance to irradiation or cisplatin in A549 cells significantly (n = 3, *<i>P</i> < 0.05).</p

Expression of let-7 family miRNAs was down-regulated in radio- or chemo-resistant cells.

<p><b>(A)</b> Members of the let-7 family (schematic). <b>(B)</b> Down-regulation of expression of let-7 family miRNAs in microarray experiments was validated by RT-PCR (n = 3, *<i>P</i> < 0.05).</p

Dynamic analyses of expression of let-7 and LIN28 during induction of radio- or chemo-resistance in A549 cells.

<p><b>(A)</b> To varying degrees, expression of let-7 miRNAs was down-regulated during induction of radio- or chemo-resistance. <b>(B)</b> To varying degrees, expression of LIN28A and LIN28B was up-regulated during induction of radio- or chemo-resistance.</p

Let-7 and LIN28 were putative regulators of single-cell proliferative capability.

<p><b>(A)</b> Colony-formation assay of A549/IR and A549/DDP cells transfected with let-7 mimics or si-LIN28A. <b>(B)</b> Colony-formation assay of A549 cells transfected with let-7 inhibitors or LIN28A plasmids (n = 3, *<i>P</i> < 0.05).</p